2025 Guide: How to Get Planning Permission for a House Extension in London

salmanysf
1 day ago
2 min read

📝 Step 1: Know If You Need Planning Permission

Not all extensions need planning permission. Some fall under Permitted Development (PD) — a set of rights that allow minor extensions without full planning approval.

You can use PD if:

The extension is under 3m (semi or terrace) or 4m (detached)
Materials match the existing property
No balconies, verandas, or raised platforms
It doesn’t cover more than 50% of the garden
Not in a Conservation Area, flat, or Article 4 zone

✅ For 6m or 8m rear extensions, you can apply under the Neighbour Consultation Scheme (Prior Approval).

⚠️ Important: Many West London boroughs, like Richmond and parts of Hounslow, have Article 4 directions that remove PD rights.

🧱 Step 2: Decide the Type of Extension

Each extension type has different planning implications:

Extension Type	Planning Needed?
Rear Single Storey	Often under PD / Prior Approval
Side Infill	Usually full planning
Wraparound Extension	Always full planning
Double Storey Extension	Full planning
Loft + Extension Combo	Full planning + structural calcs

We can advise the best route depending on your property type, location, and council policies.

📐 Step 3: Prepare Planning Drawings

A professional planning application must include:

Existing & proposed floor plans
Elevations and sections
Site plan and block plan
Design & Access Statement (if required)
Planning application form (via Planning Portal)

💡 SY Design Studio handles all drawings, form submissions, and liaison with the council. We also advise you on how to maximise internal space while staying compliant.

📤 Step 4: Submit the Application

We submit the application via the Planning Portal and manage it through your local authority (e.g. Hounslow, Ealing, etc.).

The process includes:

Application validation
21-day neighbour consultation
Case officer site visit (sometimes)
Decision within 8 weeks

You’ll receive a decision notice — Approved, Refused, or Request for Amendments.

🔁 Step 5: Amend or Appeal (if needed)

If refused, we’ll:

Review the officer’s feedback
Amend the design to meet policy
Re-submit the application
Or lodge a planning appeal (if appropriate)

✅ Planning Permission Secured? Now for Building Control

Once planning is approved, you’ll still need:

Building Regulations Drawings
Structural Calculations (steel beams, padstones, etc.)
Build-Over Agreements (if near a drain)
Party Wall Notices (if adjoining a neighbour)

SY Design Studio can handle all stages — from planning to building control and even structural design.

📍 Recent West London Projects:

✅ 6m Rear Extension in Southall – Approved via Prior Approval✅ Double-Storey Extension in Hounslow – Approved under full planning✅ Side Infill + Loft in Ealing – Full application + building control drawings

Want us to review your extension idea for FREE? Just send us your postcode and a photo of your rear garden.

💬 Client Review

"The team at SY Design Studio were brilliant from start to finish. Our planning application was approved on the first attempt — and their drawings were spot on for our builder to work from!"— Mr. Patel, Ealing

📞 Ready to Extend Your Home?

Let us handle everything — planning drawings, structural design, and council submissions.

👉 Visit www.sydesignstudio.co .uk📞 Call us for a free quote today📍 Based in Hounslow | Serving West London & Surrounding Areas